Question

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Answer 1

Bài 5:
\(A+9=\frac{10}{1}+\frac{10}{2}+\frac{10}{3}+....+\frac{10}{9}\)

\(A=\frac{10}{2}+\frac{10}{2}+\frac{10}{3}+...+\frac{10}{9}+1=\frac{10}{2}+\frac{10}{3}+...+\frac{10}{9}+\frac{10}{10}\)

\(A=10\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{10}\right)=10B\)

$\Rightarrow A:B=10$

 

Answer 2

Answer 3